Method of providing MTC monitoring related information

ABSTRACT

A method for adjusting a timer value for a device includes determining, by a home subscribing server (HSS), a timer value for a routing area update (RAU) or a tracking area update (TAU) based on a maximum time period, wherein the timer value for the RAU or the TAU is determined to be a smaller value than the maximum time period, wherein the maximum time period is related to a loss of a connectivity indicating the device is no longer possible to be signaled, and delivering, by the HSS, information regarding the determined timer value for the RAU or the TAU to a Mobility Management Entity (MME)/Serving General Packet Radio Service (GPRS) Supporting Node (SGSN).

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of U.S. patent application Ser. No.14/436,764 filed on Apr. 17, 2015 (now U.S. Pat. No. 10,015,621 issuedon Jul. 3, 2018), which is the National Phase of PCT InternationalApplication No. PCT/KR2013/007694 filed on Aug. 28, 2013, which claimsthe priority benefit under 35 U.S.C. § 119(e) to U.S. ProvisionalApplication Nos. 61/862,090 filed on Aug. 5, 2013, 61/819,656 filed onMay 6, 2013 and 61/715,292 filed on Oct. 18, 2012, all of which arehereby expressly incorporated by reference into the present application.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a Machine Type Communication (MTC)monitoring method.

Discussion of the Related Art

In 3GPP in which technical standards for mobile communication systemsare established, in order to handle 4th generation communication andseveral related forums and new technologies, research on Long TermEvolution/System Architecture Evolution (LTE/SAE) technology has startedas part of efforts to optimize and improve the performance of 3GPPtechnologies from the end of the year 2004.

SAE that has been performed based on 3GPP SA WG2 is research regardingnetwork technology that aims to determine the structure of a network andto support mobility between heterogeneous networks in line with an LTEtask of a 3GPP TSG RAN and is one of recent important standardizationissues of 3GPP. SAE is a task for developing a 3GPP system into a systemthat supports various radio access technologies based on an IP, and thetask has been carried out for the purpose of an optimized packet-basedsystem which minimizes transmission delay with a more improved datatransmission capability.

An Evolved Packet System (EPS) higher level reference model defined in3GPP SA WG2 includes a non-roaming case and roaming cases having variousscenarios, and for details therefor, reference can be made to 3GPPstandard documents TS 23.401 and TS 23.402. A network configuration ofFIG. 1 has been briefly reconfigured from the EPS higher level referencemodel.

FIG. 1 shows the configuration of an evolved mobile communicationnetwork.

An Evolved Packet Core (EPC) may include various elements. FIG. 1illustrates a Serving Gateway (S-GW) 52, a Packet Data Network Gateway(PDN GW) 53, a Mobility Management Entity (MME) 51, a Serving GeneralPacket Radio Service (GPRS) Supporting Node (SGSN), and an enhancedPacket Data Gateway (ePDG) that correspond to some of the variouselements.

The S-GW 52 is an element that operates at a boundary point between aRadio Access Network (RAN) and a core network and has a function ofmaintaining a data path between an eNodeB 22 and the PDN GW 53.Furthermore, if a terminal (or User Equipment (UE) moves in a region inwhich service is provided by the eNodeB 22, the S-GW 52 plays a role ofa local mobility anchor point. That is, for mobility within an E-UTRAN(i.e., a Universal Mobile Telecommunications System (Evolved-UMTS)Terrestrial Radio Access Network defined after 3GPP release-8), packetscan be routed through the S-GW 52. Furthermore, the S-GW 52 may play arole of an anchor point for mobility with another 3GPP network (i.e., aRAN defined prior to 3GPP release-8, for example, a UTRAN or GlobalSystem for Mobile communication (GSM) (GERAN)/Enhanced Data rates forGlobal Evolution (EDGE) Radio Access Network).

The PDN GW (or P-GW) 53 corresponds to the termination point of a datainterface toward a packet data network. The PDN GW 53 can support policyenforcement features, packet filtering, charging support, etc.Furthermore, the PDN GW (or P-GW) 53 can play a role of an anchor pointfor mobility management with a 3GPP network and a non-3GPP network(e.g., an unreliable network, such as an Interworking Wireless LocalArea Network (I-WLAN), a Code Division Multiple Access (CDMA) network,or a reliable network, such as WiMax).

In the network configuration of FIG. 1, the S-GW 52 and the PDN GW 53have been illustrated as being separate gateways, but the two gatewaysmay be implemented in accordance with a single gateway configurationoption.

The MME 51 is an element for performing the access of a terminal to anetwork connection and signaling and control functions for supportingthe allocation, tracking, paging, roaming, handover, etc. of networkresources. The MME 51 controls control plane functions related tosubscribers and session management. The MME 51 manages numerous eNodeBs22 and performs conventional signaling for selecting a gateway forhandover to another 2G/3G networks. Furthermore, the MME 51 performsfunctions, such as security procedures, terminal-to-network sessionhandling, and idle terminal location management.

The SGSN handles all packet data, such as a user's mobility managementand authentication for different access 3GPP networks (e.g., a GPRSnetwork and an UTRAN/GERAN).

The ePDG plays a role of a security node for an unreliable non-3GPPnetwork (e.g., an I-WLAN and a Wi-Fi hotspot).

As described with reference to FIG. 1, a terminal (or UE) having an IPcapability can access an IP service network (e.g., IMS), provided by aservice provider (i.e., an operator), via various elements within an EPCbased on non-3GPP access as well as based on 3GPP access.

Furthermore, FIG. 1 shows various reference points (e.g., S1-U andS1-MME). In a 3GPP system, a conceptual link that connects two functionsthat are present in the different function entities of an E-UTRAN and anEPC is called a reference point. Table 1 below defines reference pointsshown in FIG. 1. In addition to the reference points shown in theexample of Table 1, various reference points may be present depending ona network configuration.

TABLE 1 REFERENCE POINT DESCRIPTION S1-MME A reference point for acontrol plane protocol between the E-UTRAN and the MME S1-U A referencepoint between the E-UTRAN and the S-GW for path switching betweeneNodeBs during handover and user plane tunneling per bearer S3 Areference point between the MME and the SGSN that provides the exchangeof pieces of user and bearer information for mobility between 3GPPaccess networks in idle and/or activation state. This reference pointcan be used intra-PLMN or inter-PLMN (e.g. in the case of Inter-PLMNHO). S4 A reference point between the SGW and the SGSN that providesrelated control and mobility support between the 3GPP anchor functionsof a GPRS core and the S-GW. Furthermore, if a direct tunnel is notestablished, the reference point provides user plane tunneling. S5 Areference point that provides user plane tunneling and tunnel managementbetween the S-GW and the PDN GW. The reference point is used for S-GWrelocation due to UE mobility and if the S-GW needs to connect to anon-collocated PDN GW for required PDN connectivity S11 A referencepoint between the MME and the S-GW SGi A reference point between the PDNGW and the PDN. The PDN may be a public or private PDN external to anoperator or may be an intra-operator PDN, e.g., for the providing of IMSservices. This reference point corresponds to Gi for 3GPP access.

Among the reference points shown in FIG. 1, S2a and S2b correspond tonon-3GPP interfaces. S2a is a reference point providing the user planewith related control and mobility support between a PDN GW and areliable non-3GPP access. S2b is a reference point providing the userplane with mobility support and related control between a PDN GW and anePDG.

FIG. 2 is an exemplary diagram showing the architecture of a commonE-UTRAN and a common EPC.

As shown in FIG. 2, the eNodeB 20 can perform functions, such as routingto a gateway while RRC connection is activated, the scheduling andtransmission of a paging message, the scheduling and transmission of abroadcast channel (BCH), the dynamic allocation of resources to UE inuplink and downlink, a configuration and providing for the measurementof the eNodeB 20, control of a radio bearer, radio admission control,and connection mobility control. The EPC can perform functions, such asthe generation of paging, the management of an LTE_IDLE state, theciphering of a user plane, control of an EPS bearer, the ciphering ofNAS signaling, and integrity protection.

FIG. 3 is an exemplary diagram showing the structure of a radiointerface protocol in a control plane between UE and an eNodeB, and FIG.4 is another exemplary diagram showing the structure of a radiointerface protocol in a control plane between UE and an eNodeB.

The radio interface protocol is based on a 3GPP radio access networkstandard. The radio interface protocol includes a physical layer, a datalink layer, and a network layer horizontally, and it is divided into auser plane for the transmission of information and a control plane forthe transfer of a control signal (or signaling).

The protocol layers may be classified into a first layer (L1), a secondlayer (L2), and a third layer (L3) based on three lower layers of theOpen System Interconnection (OSI) reference model that is widely knownin communication systems.

The layers of the radio protocol of the control plane shown in FIG. 3and the radio protocol in the user plane of FIG. 4 are described below.

The physical layer PHY, that is, the first layer, provides informationtransfer service using physical channels. The PHY layer is connected toa Medium Access Control (MAC) layer placed in a higher layer through atransport channel, and data is transferred between the MAC layer and thePHY layer through the transport channel. Furthermore, data istransferred between different PHY layers, that is, PHY layers on thesender side and the receiver side, through the PHY layer.

A physical channel is made up of multiple subframes on a time axis andmultiple subcarriers on a frequency axis. Here, one subframe is made upof a plurality of symbols and a plurality of subcarriers on the timeaxis. One subframe is made up of a plurality of resource blocks, and oneresource block is made up of a plurality of symbols and a plurality ofsubcarriers. A Transmission Time Interval (TTI), that is, a unit timeduring which data is transmitted, is 1 ms corresponding to one subframe.

In accordance with 3GPP LTE, physical channels that are present in thephysical layer of the sender side and the receiver side can be dividedinto a Physical Downlink Shared Channel (PDSCH) and a Physical UplinkShared Channel (PUSCH), that is, data channels, and a Physical DownlinkControl Channel (PDCCH), a Physical Control Format Indicator Channel(PCFICH), a Physical Hybrid-ARQ Indicator Channel (PHICH), and aPhysical Uplink Control Channel (PUCCH), that is, control channels.

A PCFICH that is transmitted in the first OFDM symbol of a subframecarries a Control Format Indicator (CFI) regarding the number of OFDMsymbols (i.e., the size of a control region) used to send controlchannels within the subframe. A wireless device first receives a CFI ona PCFICH and then monitors PDCCHs.

Unlike a PDCCH, a PCFICH is transmitted through the fixed PCFICHresources of a subframe without using blind decoding.

A PHICH carries positive-acknowledgement (ACK)/negative-acknowledgement(NACK) signals for an uplink (UL) Hybrid Automatic Repeat reQuest(HARQ). ACK/NACK signals for UL data on a PUSCH that is transmitted by awireless device are transmitted on a PHICH.

A Physical Broadcast Channel (PBCH) is transmitted in four former OFDMsymbols of the second slot of the first subframe of a radio frame. ThePBCH carries system information that is essential for a wireless deviceto communicate with an eNodeB, and system information transmittedthrough a PBCH is called a Master Information Block (MIB). In contrast,system information transmitted on a PDSCH indicated by a PDCCH is calleda System Information Block (SIB).

A PDCCH can carry the resource allocation and transport format of adownlink-shared channel (DL-SCH), information about the resourceallocation of an uplink shared channel (UL-SCH), paging information fora PCH, system information for a DL-SCH, the resource allocation of anupper layer control message transmitted on a PDSCH, such as a randomaccess response, a set of transmit power control commands for pieces ofUE within a specific UE group, and the activation of a Voice overInternet Protocol (VoIP). A plurality of PDCCHs can be transmittedwithin the control region, and UE can monitor a plurality of PDCCHs. APDCCH is transmitted on one Control Channel Element (CCE) or anaggregation of multiple contiguous CCEs. A CCE is a logical allocationunit used to provide a PDCCH with a coding rate according to the stateof a radio channel. A CCE corresponds to a plurality of resource elementgroups. The format of a PDCCH and the number of bits of a possible PDCCHare determined by a relationship between the number of CCEs and a codingrate provided by CCEs.

Control information transmitted through a PDCCH is called DownlinkControl Information (DCI). DCI can include the resource allocation of aPDSCH (also called a downlink (DL) grant)), the resource allocation of aPUSCH (also called an uplink (UL) grant), a set of transmit powercontrol commands for pieces of UE within a specific UE group, and/or theactivation of a Voice over Internet Protocol (VoIP).

Several layers are present in the second layer. First, a Medium AccessControl (MAC) layer functions to map various logical channels to varioustransport channels and also plays a role of logical channel multiplexingfor mapping multiple logical channels to one transport channel. The MAClayer is connected to a Radio Link Control (RLC) layer, that is, ahigher layer, through a logical channel. The logical channel isbasically divided into a control channel through which information ofthe control plane is transmitted and a traffic channel through whichinformation of the user plane is transmitted depending on the type oftransmitted information.

The RLC layer of the second layer functions to control a data size thatis suitable for sending, by a lower layer, data received from a higherlayer in a radio section by segmenting and concatenating the data.Furthermore, in order to guarantee various types of QoS required byradio bearers, the RLC layer provides three types of operation modes: aTransparent Mode (TM), an Un-acknowledged Mode (UM), and an AcknowledgedMode (AM). In particular, AM RLC performs a retransmission functionthrough an Automatic Repeat and Request (ARQ) function for reliable datatransmission.

The Packet Data Convergence Protocol (PDCP) layer of the second layerperforms a header compression function for reducing the size of an IPpacket header containing control information that is relatively large insize and unnecessary in order to efficiently send an IP packet, such asIPv4 or IPv6, in a radio section having a small bandwidth when sendingthe IP packet. Accordingly, transmission efficiency of the radio sectioncan be increased because only essential information is transmitted inthe header part of data. Furthermore, in an LTE system, the PDCP layeralso performs a security function. The security function includesciphering for preventing the interception of data by a third party andintegrity protection for preventing the manipulation of data by a thirdparty.

A Radio Resource Control (RRC) layer at the highest place of the thirdlayer is defined only in the control plane and is responsible forcontrol of logical channels, transport channels, and physical channelsin relation to the configuration, re-configuration, and release of RadioBearers (RBs). Here, the RB means service provided by the second layerin order to transfer data between UE and an E-UTRAN.

If an RRC connection is present between the RRC layer of UE and the RRClayer of a wireless network, the UE is in an RRC_CONNECTED state. Ifnot, the UE is in an RRC_IDLE state.

An RRC state and an RRC connection method of UE are described below. TheRRC state means whether or not the RRC layer of UE has been logicallyconnected to the RRC layer of an E-UTRAN. If the RRC layer of UE islogically connected to the RRC layer of an E-UTRAN, it is called theRRC_CONNECTED state. If the RRC layer of UE is not logically connectedto the RRC layer of an E-UTRAN, it is called the RRC_IDLE state. SinceUE in the RRC_CONNECTED state has an RRC connection, an E-UTRAN cancheck the existence of the UE in a cell unit, and thus control the UEeffectively. In contrast, if UE is in the RRC_IDLE state, an E-UTRANcannot check the existence of the UE, and a core network is managed in aTracking Area (TA) unit, that is, an area unit greater than a cell. Thatis, only the existence of UE in the RRC_IDLE state is checked in an areaunit greater than a cell. In such a case, the UE needs to shift to theRRC_CONNECTED state in order to be provided with common mobilecommunication service, such as voice or data. Each TA is classifiedthrough Tracking Area Identity (TAI). UE can configure TAI throughTracking Area Code (TAC), that is, information broadcasted by a cell.

When a user first turns on the power of UE, the UE first searches for aproper cell, establishes an RRC connection in the corresponding cell,and registers information about the UE with a core network. Thereafter,the UE stays in the RRC_IDLE state. The UE in the RRC_IDLE state(re)selects a cell if necessary and checks system information or paginginformation. This process is called camp on. When the UE in the RRC_IDLEstate needs to establish an RRC connection, the UE establishes an RRCconnection with the RRC layer of an E-UTRAN through an RRC connectionprocedure and shifts to the RRC_CONNECTED state. A case where the UE inthe RRC_IDLE state needs to establish with an RRC connection includesmultiple cases. The multiple cases may include, for example, a casewhere UL data needs to be transmitted for a reason, such as a callattempt made by a user and a case where a response message needs to betransmitted in response to a paging message received from an E-UTRAN.

A Non-Access Stratum (NAS) layer placed over the RRC layer performsfunctions, such as session management and mobility management.

The NAS layer shown in FIG. 3 is described in detail below.

Evolved Session Management (ESM) belonging to the NAS layer performsfunctions, such as the management of default bearers and the managementof dedicated bearers, and ESM is responsible for control that isnecessary for UE to use PS service from a network. Default bearerresources are characterized in that they are allocated by a network whenUE first accesses a specific Packet Data Network (PDN) or accesses anetwork. Here, the network allocates an IP address available for UE sothat the UE can use data service and the QoS of a default bearer. LTEsupports two types of bearers: a bearer having Guaranteed Bit Rate (GBR)QoS characteristic that guarantees a specific bandwidth for thetransmission and reception of data and a non-GBR bearer having the besteffort QoS characteristic without guaranteeing a bandwidth. A defaultbearer is assigned a non-GBR bearer, and a dedicated bearer may beassigned a bearer having a GBR or non-GBR QoS characteristic.

In a network, a bearer assigned to UE is called an Evolved PacketService (EPS) bearer. When assigning an EPS bearer, a network assignsone ID. This is called an EPS bearer ID. One EPS bearer has QoScharacteristics of a Maximum Bit Rate (MBR) and a Guaranteed Bit Rate(GBR) or an Aggregated Maximum Bit Rate (AMBR).

FIG. 5 is a flowchart illustrating a random access process in 3GPP LTE.

The random access process is used for UE 10 to obtain UL synchronizationwith a base station, that is, an eNodeB 20, or to be assigned UL radioresources.

The UE 10 receives a root index and a physical random access channel(PRACH) configuration index from the eNodeB 20. 64 candidate randomaccess preambles defined by a Zadoff-Chu (ZC) sequence are present ineach cell. The root index is a logical index that is used for the UE togenerate the 64 candidate random access preambles.

The transmission of a random access preamble is limited to specific timeand frequency resources in each cell. The PRACH configuration indexindicates a specific subframe on which a random access preamble can betransmitted and a preamble format.

The UE 10 sends a randomly selected random access preamble to the eNodeB20. Here, the UE 10 selects one of the 64 candidate random accesspreambles. Furthermore, the UE selects a subframe corresponding to thePRACH configuration index. The UE 10 sends the selected random accesspreamble in the selected subframe.

The eNodeB 20 that has received the random access preamble sends aRandom Access Response (RAR) to the UE 10. The random access response isdetected in two steps. First, the UE 10 detects a PDCCH masked with arandom access-RNTI (RA-RNTI). The UE 10 receives a random accessresponse within a Medium Access Control (MAC) Protocol Data Unit (PDU)on a PDSCH that is indicated by the detected PDCCH.

FIG. 6 illustrates a connection process in a radio resource control(RRC) layer.

FIG. 6 shows an RRC state depending on whether there is an RRCconnection. The RRC state denotes whether the entity of the RRC layer ofUE 10 is in logical connection with the entity of the RRC layer ofeNodeB 20, and if yes, it is referred to as RRC connected state, and ifno as RRC idle state.

In the connected state, UE 10 has an RRC connection, and thus, theE-UTRAN may grasp the presence of the UE on a cell basis and may thuseffectively control UE 10. In contrast, UE 10 in the idle state cannotgrasp eNodeB 20 and is managed by a core network on the basis of atracking area that is larger than a cell. The tracking area is a set ofcells. That is, UE 10 in the idle state is grasped for its presence onlyon a larger area basis, and the UE should switch to the connected stateto receive a typical mobile communication service such as voice or dataservice.

When the user turns on UE 10, UE 10 searches for a proper cell and staysin idle state in the cell. UE 10, when required, establishes an RRCconnection with the RRC layer of eNodeB 20 through an RRC connectionprocedure and transits to the RRC connected state.

There are a number of situations where the UE staying in the idle stateneeds to establish an RRC connection, for example, when the userattempts to call or when uplink data transmission is needed, or whentransmitting a message responsive to reception of a paging message fromthe EUTRAN.

In order for the idle UE 10 to be RRC connected with eNodeB 20, UE 10needs to perform the RRC connection procedure as described above. TheRRC connection procedure generally comes with the process in which UE 10transmits an RRC connection request message to eNodeB 20, the process inwhich eNodeB 20 transmits an RRC connection setup message to UE 10, andthe process in which UE 10 transmits an RRC connection setup completemessage to eNodeB 20. The processes are described in further detail withreference to FIG. 6.

1) The idle UE 10, when attempting to establish an RRC connection, e.g.,for attempting to call or transmit data or responding to paging fromeNodeB 20, sends an RRC connection request message to eNodeB 20.

2) When receiving the RRC connection message from UE 10, eNodeB 20accepts the RRC connection request from UE 10 if there are enough radioresources, and eNodeB 20 sends a response message, RRC connection setupmessage, to UE 10.

3) When receiving the RRC connection setup message, UE 10 transmits anRRC connection setup complete message to eNodeB 20. If UE 10successfully transmits the RRC connection setup message, UE 10 happensto establish an RRC connection with eNodeB 20 and switches to the RRCconnected state.

FIG. 7 shows a 3GPP service model for supporting MTC.

A Machine Type Communication (MTC) device may be used in a mobilecommunication system. MTC implies communication between one machine andanother machine or between a machine and a server, excluding a humanintervention. A device used in this case is called the MTC device, and aserver used in this case is called an MTC server. A service providedthrough the MTC device is distinguished from a communication servicebased on the human intervention, and may be applied to various ranges ofservices.

The aforementioned MTC device is a communication device for performingcommunication between one machine and another machine or between amachine and a server, and is not much different from a User Equipment(UE) with a human intervention, except that the human intervention isexcluded. That is, the MTC device may correspond to the UE excluding thehuman intervention. However, in terms of excluding the humanintervention, some problems may occur if a messagetransmission/reception method (e.g., a paging messagetransmission/reception method) of the UE with the human intervention isuniformly applied to the MTC device.

To support the MTC, although it is defined that communication isachieved through a PS network in GSM/UMTS/EPS of the 3GPP standard, amethod also applicable to a CS network is described in the presentspecification.

A UE used for the MTC (or an MTC UE) and an end-to-end applicationbetween MTC applications may use services provided by a 3GPP system andselective services provided by the MTC server. The 3GPP system mayinclude transmission and communication services (including a 3GPP bearerservice, an IMS, and an SMS) including various optimizations forfacilitating the MTC. It is shown in FIG. 7 that the UE used for the MTCis connected to a 3GPP network (e.g., UTRAN, E-UTRAN, GERAN, I-WLAN,etc.) through an Um/Uu/LTE-Uu interface. The architecture of FIG. 7includes various MTC models (e.g., a direct model, an indirect model,and a hybrid model).

Entities shown in FIG. 7 are now described.

In FIG. 7, an application server is a server on a network on which anMTC application is executed. The aforementioned various techniques forimplementing the MTC applications may be applied to the MTC applicationserver, and a detailed description thereof will be omitted. In addition,in FIG. 7, the MTC application server may access the MTC server througha reference point API, and a detailed description thereof will beomitted. Alternatively, the MTC application server may be collocatedwith the MTC server.

The MTC server (e.g., a Services Capability Server (SCS) shown in thefigure) is a server on a network for managing an MTC UE, and may beconnected to a 3GPP network to communicate with a UE used for MTC andnodes of PLMN.

An MTC-InterWorking Function (MTC-IWF) may control interworking betweenan MTC server and an operator core network, and may play a role of aproxy of an MTC operation. To support the MTC indirect or hybrid model,one or more MTC-IWFs may exist in a Home PLMN (HPLMN). The MTC-IWF mayrelay or interpret a signaling protocol on a reference point Tsp tooperate a specific function in the PLMN. The MTC-IWF may perform afunction for authenticating an MTC server before the MTC serverestablishes communication with a 3GPP network, a function forauthenticating a control plane request from the MTC server, variousfunctions related to a trigger indication, etc.

An SMS-SC (Short Message Service-Service Center)/IP-SM-GW (InternetProtocol Short Message GateWay) may manage transmission/reception of aShort Message Service (SMS). The SMS-SC may relay a short messagebetween a Short Message Entity (SME) (i.e., an entity for transmittingor receiving a short message) and a mobile station and may serve for astoring-and-delivering function. The IP-SM-GW may serve for a protocolinteraction between an IP-based UE and the SMS-SC.

A CDF (Charging Data Function)/CGF (Charging Gateway Function) mayperform an accounting related operation.

An HLR/HSS may perform a function for storing subscriber information(e.g., IMSI, etc.), routing information, configuration information,etc., and for providing it to the MTC-IWF.

An MSC/SGSN/MME may perform a control function such as mobilitymanagement, authentication, resource allocation, etc., for networkconnection of the UE. Regarding triggering, a function for receiving atrigger indication from the MTC-IWF and for processing it in a form of amessage provided to the MTC UE may be performed.

A GGSN (Gateway GPRS Support Node)/S-GW (Serving-Gateway)+P-GW (PacketData Network-Gateway) may perform a function of a gateway which servesfor connection of a core network and an external network.

Table 2 below is a summary of an important reference point in FIG. 7.

TABLE 2 Reference point Description Tsms It is the reference point usedby an entity outside the 3GPP system to communicate with UEs used forMTC through an SMS. Tsp It is the reference point used by an entityoutside the 3GPP system to communicate with the MTC-IWF related controlplane signaling. T4 Reference point used by the MTC-IWF to route devicetrigger to the SMS- SC in the HPLMN. T5a Reference point used betweenthe MTC-IWF and the serving SGSN. T5b Reference point used between theMTC-IWF and the serving MME. T5c Reference point used between theMTC-IWF and the serving MSC. S6m Reference point used by the MTC-IWF tointerrrogate the HSS/HLR for E.164 MSISDN (Mobile Station InternationalSubscriber Directory Number) or external identifier mapping to IMSI andgather UE reachability and configuration information.

At least one of the reference points T5a, T5b, and T5c is referred to asT5.

Meanwhile, user plane communication with the MTC server in case of theindirect and hybrid model and communication with the MTC application incase of the direct and hybrid model may be performed by using theexisting protocol through reference points Gi and SGi.

The 3GPP TS 23.682 document may be incorporated by reference for detailsof the description of FIG. 7.

FIG. 8 shows an example of a service via an MTC device.

The service via the MTC device may be classified into several types. Forexample, there is a service for collecting a variety of information bythe MTC device.

Referring to FIG. 8, as an example of the aforementioned service, it isshown that a measuring service, a road information service, a userelectronic device control service, etc., can be provided via the MTCdevice. Herein, when the MTC device collects measuring information, roadtraffic information, etc., and transmits it to an eNodeB, the eNodeB maytransmit it to an MTC server, and an MTC user may use a providedservice.

A 3GPP service model/system for supporting MTC may provide a monitoringfunction/service for managing the MTC device. For example, a 3GPP systemmay detect the following event and report the detected event to the MTCserver, so that the MTC user is allowed to easily manage the MTC device.

-   -   The MTC device performs an operation not suitable for an        activated MTC feature(s).    -   Change in an association between the MTC device and a UICC.    -   The MTC device has lost a connectivity to a network. A maximum        time between a time at which the connectivity is actually lost        and a time at which the connectivity loss is detected is        configurable in unit of subscribers.    -   Communication failure event and its cause.    -   Location change (a geographical position and/or a point of        attachment in the network of the MTC device).

Although the MTC device can be monitored as described above, a detailedprocedure and solution thereof have not been provided. Therefore,conventionally, the aforementioned services are only imperfect orinfeasible techniques in practice.

SUMMARY OF THE INVENTION

Accordingly, an aspect of the present specification is to provide amethod of solving the above-mentioned problems.

To achieve the aforementioned purpose, the present specification is toprovide a method of providing information for MTC (Machine typecommunication) monitoring. The method may performed by a subscriberinformation server and comprise: receiving information regarding amonitoring related timer for any MTC device from an MTC related server;if there is information regarding a periodic access or location updaterelated timer for the MTC device, adjusting any one of the monitoringrelated timer and the periodic access or location update related timeron the basis of the other one; and delivering information regarding theadjusted timer to the MTC related server or a node served formonitoring.

To achieve the aforementioned purpose, the present specification is toprovide a method of providing information for MTC (Machine typecommunication) monitoring. The method may be performed by a network nodeand comprise: receiving information regarding a monitoring related timerfor any MTC device from an MTC related server; acquiring informationregarding a periodic access or location update related timer for the MTCdevice; adjusting any one of the monitoring related timer and theperiodic access or location update related timer on the basis of theother one; performing monitoring on the basis of information regardingthe adjusted timer; and providing the information regarding the adjustedtimer to the MTC device.

The periodic access or location update related timer has one or more of:a timer value for a periodic RAU (Routing Area Update); a timer valuefor an RAU with a longer period; a timer value for a periodic TAU(Tracking Area Update); and a timer value for a TAU with a longerperiod.

The periodic access or location update related timer has one or more of:a T3312 value for an RAU; a T3312 extended value; a T3412 value for aTAU; and a T3412 extended value.

The monitoring related timer has one or more of: a time value capable ofdetermining that a monitoring event is detected; and a period value fordetecting whether the monitoring event is generated.

The adjusting additionally considers one or more of: subscriberinformation; capability information or priority information of the MTCdevice; operator policy information; MTC monitoring related information;information acquired from another node; network status information;information associated with a mobility management related operation; andinformation association with a session management related operation.

In the adjusting, the periodic access or location update relater timeris adjusted on the basis of the monitoring related timer, or themonitoring related timer is adjusted on the basis of the periodic accessor location update related timer.

The MTC related server is an MTC-IWF (Machine TypeCommunications-InterWorking Function), a service capability server, oran application server. The node served for monitoring is an MME(Mobility Management Entity) or an SGSN (Serving GPRS Support Node).

According to an aspect of the present specification, there is providedan effective Machine Type Communication (MTC) monitoring method. Thatis, according to an aspect of the present specification, it is possibleto perform MTC related monitoring for confirming whether an access to acore network by an MTC device is normally achieved or whether aconnection to a network is valid with a specific period. It is alsopossible to perform MTC related monitoring for confirming an accesslocation for the MTC device or a change in the access location with aspecific period.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the configuration of an evolved mobile communicationnetwork.

FIG. 2 is an exemplary diagram showing the architecture of a commonEvolved Universal Terrestrial Radio Access Network (E-UTRAN) and acommon Evolved PAcket Core (EPC).

FIG. 3 is an exemplary diagram showing the structure of a radiointerface protocol in a control plane between a User Equipment (UE) andan evolved NodeB (eNodeB).

FIG. 4 is another exemplary diagram showing the structure of a radiointerface protocol in a control plane between a UE and an eNodeB.

FIG. 5 is a flowchart illustrating a random access process in 3rdGeneration Partnership Project (3GPP) Long Term Evolution (LTE).

FIG. 6 shows a connection process in a Radio Resource Control (RRC)layer.

FIG. 7 shows a 3GPP service model for supporting Machine TypeCommunication (MTC).

FIG. 8 shows an example of a service via an MTC device.

FIG. 9 is a signal flow diagram showing a process of preformingMTC-related monitoring by a network node.

FIG. 10 shows a procedure in which an MTC device accesses a corenetwork.

FIG. 11 is a flowchart showing a procedure of performing MTC monitoringaccording to a first method proposed in the present specification.

FIG. 12 is a flowchart showing another procedure of performing MTCmonitoring according to a first method proposed in the presentspecification.

FIG. 13 is a flowchart showing a procedure of performing MTC monitoringaccording to a second method proposed in the present specification.

FIG. 14 is a flowchart showing another procedure of performing MTCmonitoring according to a second method proposed in the presentspecification.

FIG. 15 shows a modified example for the methods shown in FIG. 13 andFIG. 14.

FIG. 16 shows a modified example for the methods shown in FIG. 11 toFIG. 15.

FIG. 17 is a block diagram showing a structure of a network nodeaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is described in light of UMTS (Universal MobileTelecommunication System) and EPC (Evolved Packet Core), but not limitedto such communication systems, and may be rather applicable to allcommunication systems and methods to which the technical spirit of thepresent invention may apply.

The technical terms used herein are used to merely describe specificembodiments and should not be construed as limiting the presentinvention. Further, the technical terms used herein should be, unlessdefined otherwise, interpreted as having meanings generally understoodby those skilled in the art but not too broadly or too narrowly.Further, the technical terms used herein, which are determined not toexactly represent the spirit of the invention, should be replaced by orunderstood by such technical terms as being able to be exactlyunderstood by those skilled in the art. Further, the general terms usedherein should be interpreted in the context as defined in thedictionary, but not in an excessively narrowed manner.

The expression of the singular number in the specification includes themeaning of the plural number unless the meaning of the singular numberis definitely different from that of the plural number in the context.In the following description, the term ‘include’ or ‘have’ may representthe existence of a feature, a number, a step, an operation, a component,a part or the combination thereof described in the specification, andmay not exclude the existence or addition of another feature, anothernumber, another step, another operation, another component, another partor the combination thereof.

The terms ‘first’ and ‘second’ are used for the purpose of explanationabout various components, and the components are not limited to theterms ‘first’ and ‘second’. The terms ‘first’ and ‘second’ are only usedto distinguish one component from another component. For example, afirst component may be named as a second component without deviatingfrom the scope of the present invention.

It will be understood that when an element or layer is referred to asbeing “connected to” or “coupled to” another element or layer, it can bedirectly connected or coupled to the other element or layer orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly connected to” or “directlycoupled to” another element or layer, there are no intervening elementsor layers present.

Hereinafter, exemplary embodiments of the present invention will bedescribed in greater detail with reference to the accompanying drawings.In describing the present invention, for ease of understanding, the samereference numerals are used to denote the same components throughout thedrawings, and repetitive description on the same components will beomitted. Detailed description on well-known arts which are determined tomake the gist of the invention unclear will be omitted. The accompanyingdrawings are provided to merely make the spirit of the invention readilyunderstood, but not should be intended to be limiting of the invention.It should be understood that the spirit of the invention may be expandedto its modifications, replacements or equivalents in addition to what isshown in the drawings.

In the drawings, user equipments (UEs) are shown for example. The UE mayalso be denoted a terminal or mobile equipment (ME). The UE may be alaptop computer, a mobile phone, a PDA, a smartphone, a multimediadevice, or other portable device, or may be a stationary device such asa PC or a car mounted device.

DEFINITION OF TERMS

For a better understanding, the terms used herein are briefly definedbefore going to the detailed description of the invention with referenceto the accompanying drawings.

UMTS: stands for Universal Mobile Telecommunication System and means a3rd generation mobile communication network.

UE/MS: User Equipment/Mobile Station. Means a terminal device.

EPC: stands for Evolved Packet Core and means a core network supportiveof a long term evolution (LTE) network. An evolved version of UMTS.

EPS: stands for Evolved Packet System and means a mobile communicationsystem including a UE, an access network including LTE, and an EPC.

PDN (Public Data Network): an independent network in which a serviceproviding server is located.

PDN connection: connection from UE to PDN, i.e., association(connection) between a UE represented with an IP address and a PDNrepresented with an APN (access point name).

PDN-GW (Packet Data Network Gateway): a network node of an EPS networkperforming functions such as UE IP address allocation, packet screening& filtering, and charging data collection.

Serving GW (Serving Gateway): a network node of an EPS networkperforming functions such as mobility anchor, packet routing, idle modepacket buffering, and triggering MME to page UE.

PCRF (Policy and Charging Rule Function): an EPS network node performingpolicy decision for dynamically applying QoSs and billing policiesdifferentiated per service flow.

APN (Access Point Name): name of an access point managed by a network,provided from a UE, i.e., a character string for denoting a PDN ordistinguishing a PDN from another. Accessing a requested service ornetwork (PDN) gets through a corresponding P-GW, and an APN is a name(e.g., internet.mnc012.mcc345.gprs) pre-defined in the network to beable to discover the P-GW.

TEID (Tunnel Endpoint Identifier): End point ID of a tunnel configuredbetween nodes in a network. A TEID is configured per section by thebearer of each UE.

NodeB: a UMTS network base station. A NodeB is installed outdoors andcorresponds in cell coverage size to a macro cell.

eNodeB: an EPS (Evolved Packet System) base station and is installedoutdoors. An eNodeB corresponds in cell coverage size to a macro cell.

(e)NodeB: collectively denotes NodeB and eNodeB.

MME: stands for Mobility Management Entity and plays a role to controleach entity in an EPS to provide mobility and session for a UE.

Session: a pathway for data transmission. The unit of session mayinclude PDN, bearer, and IP flow which respectively correspond the unitof the overall target network (unit of APN or PDN), the unitdistinguished by QoS therein (unit of bearer), and unit of destinationIP address.

PDN connection: a connection from a UE to a PDN, i.e., an association(connection) between a UE represented with an IP address and a PDNrepresented with an APN. This means a connection (UE-PDN GW) betweenentities in a core network to form a session.

UE Context: information on UE's context used to manage UE in network,i.e., context information consisting of UE id, mobility (e.g., currentlocation), and session attribute (QoS, or priority).

OMA DM (Open Mobile Alliance Device Management): a protocol designed formanaging mobile devices such as mobile phones, PDAs, or portablecomputers and performs functions such as device configuration, firmwareupgrade, and error reporting.

OAM (Operation Administration and Maintenance): denotes a group ofnetwork management functions displaying network faults and providingcapability information, diagnosis and data.

NAS configuration MO (Management Object): MO (Management Object) used toconfigure in UE parameters associated with NAS functionality.

MTC: Machine Type Communication which is communication achieved betweendevices or between a device and a server without a human intervention.

MTC device: A UE which serves for a specific purpose having acommunication function through a core network, for example, a vendingmachine, a meter reading device, a weather sensor, etc. The MTC devicemay be also referred to as an MTC terminal, an MTC apparatus, an MTCmachine, an MTC UE, a UE user for MTC, a UE configured for MTC, etc.

MTC server: A server which manages the MTC device and exchanges data ona network. The server may exist outside the core network.

MTC application: An actual application using the MTC device and the MTCserver (e.g., remote meter reading, product delivery tacking, etc.).

MTC feature: A function or feature of a network for supporting theapplication. That is, some features are required according to a usage ofeach application. Examples thereof include MTC monitoring (required forremote meter reading or the like for a lost device), a low mobility(almost no movement in case of the vending machine), small datatransmission (only small amount of data is transmitted/received by theMTC device), etc.

MTC user: A user who uses a service provided by the MTC server.

NAS (Non-Access-Stratum): A higher stratum of a control plane between aUE and an MME. The NAS supports mobility management, session management,IP address management, etc., between the UE and the network.

MM (Mobility Management) operation/procedure: An operation or procedurefor mobility regulation/management/control of the UE. The MMoperation/procedure may be interpreted as including one or more of an MMoperation/procedure in a CS network, a GMM operation/procedure in a GPRSnetwork, and an EMM operation/procedure in an EPS network. The UE andthe network node (e.g., MME, SGSN, and MSC) exchange an MM message toperform the MM operation/procedure.

SM (Session Management) operation/procedure: An operation or procedurefor regulating/managing/processing/handling a user plane and/or a bearercontext/PDP context of the UE. The SM operation/procedure may beinterpreted as including one or more of an SM operation/procedure in aGPRS network and an ESM operation/procedure in an EPS network. The UEand the network node (e.g., MME and SGSN) exchange an SM message toperform the SM operation/procedure.

Low priority UE: A UE configured for NAS signalling low priority. Thestandard document 3GPP TS 24.301 and TS 24.008 may be incorporated byreference for details thereof.

Dual priority UE: A UE configured for dual priority. That is, a UE whichprovides dual priority support is configured for a NAS signaling lowpriority and also configured to override the NAS signaling low priorityindicator. The standard document 3GPP TS 24.301 and TS 24.008 may beincorporated by reference for details thereof.

Hereinafter, an aspect of the present specification is described withreference to the accompanying drawings.

FIG. 9 is a signal flow diagram showing a process of preformingMTC-related monitoring by a network node.

Referring to FIG. 9, the MTC-related monitoring may be requested to beperformed by the network node. As such, the network node performs themonitoring because it is more effective than monitoring performed by theMTC device, for example, when an event occurs in which an MTC deviceinstalled in things is detached. The MTC monitoring includes activatingmonitoring of a specific event, detecting the event, and reporting thedetected event to a verified user, e.g., an application. Upon detectionof the event, the network node may instruct a special operation such asa specific behavior, e.g., an access restriction, an allocated resourcereduction, etc.

1) More specifically, referring to FIG. 9, a Services Capability Server(SCS)/Application Server (AS) 620 transmits a monitoring action requestmessage to an MTC-IWF 610. The monitoring action request may includeevent-related data to be monitored (also called monitoring event data).The monitoring event data may include an action type field forconfiguring, activating, deactivating, or triggering a report deliveryregarding a specific monitoring event. In addition, the monitoring eventdata may further include a monitoring event ID and related parameter, amonitoring event priority, a monitoring destination node, etc. Herein,the MTC-IWF 610 as a device for performing an MTC interworking functionis connected to the MMC/Serving GPRS Support Node (SGSN) 510 through aT5b interface as shown in FIG. 7, and is connected to the SCS/AS 620through a Tsp interface.

2˜3) Upon reception of the request, the MTC-IWF 610 authenticateswhether the SCS/AS 620 has a right for the request, and confirms whetherthe request of the SCS/AS 620 is beyond a predetermined allocationcriterion. If the confirmation result shows that the request of theSCS/AS 620 is not acceptable, the MTC-IWF 610 transmits to the SCS/AS620 a monitoring action response including a cause value indicating afailure cause of the request. Otherwise, if the confirmation resultshows that the request of the SCS/AS 620 is acceptable, the MTC-IWF 610transmits to the SCS/AS 620 a monitoring action response including avalue indicating a success of the request.

4) Subsequently, the MTC-IWF 610 transmits a subscriber informationrequest message to a Home Subscription Server (HSS) 540 to confirm amonitoring configuration detail, e.g., a monitoring event ID. Herein,the monitoring event may be stored in the HSS/HLR 540 as the subscriberinformation.

5) The HSS/HLR 540 verifies the monitoring event information, andauthenticates whether an MTC-IWF which attempts to configure a networknode for the monitoring is acceptable. In addition, the HSS/HLR 540delivers to the MTC-IWF 10 the subscriber information including themonitoring event related information.

6-7) The MTC-IWF 610 determines the network node for performing themonitoring, on the basis of information received from the SCS/AS 620 andthe HSS/HLR 540. If the network node for performing the monitoring isdetermined as the MME/SGSN 510, the MTC-IWF 610 transmits to theMME/SGSN 510 a request including monitoring event data.

8) Upon reception of the request including the monitoring event data,the MME/SGSN 510 is configured to monitor the event.

Meanwhile, although the configured event may be monitored by theMME/SGSN 510, it may also be monitored by the (e)NodeB 200 and/or theP-GW 530 according to a situation.

9˜10) If the event is detected and collected through monitoringperformed by the MME/SGSN 510, a report for the collected event data maybe transmitted to the MTC-IWF 610.

11˜13) The MTC-IWF 610 confirms whether a user who will receive thereport is recorded in the subscription information.

If the information is not included in the report received from theMME/SGSN 510, an inquiry request of the SCS/AS 620 or the applicationserver is transmitted to the HSS/HLR 540. Upon reception of an inquiryresult from the HSS/HLR 540, a report for an MTC event is transmitted tothe SCS/AS 620 or application server which has confirmed the inquiry.

The method of performing the MTC-related monitoring by the network nodehas been described above.

Hereinafter, a procedure in which an MTC device 100 accesses a corenetwork is described, and a problem which may occur in the monitoringprocedure of FIG. 9 will be described.

FIG. 10 shows a procedure in which an MTC device accesses a corenetwork.

Referring to FIG. 10, an attach procedure, an RAU (Routing Area Update)procedure, and a TAU (Tracking Area Update) procedure are collectivelyillustrated. However, it should be understood such that the attachprocedure and the RAU procedure are performed when the MTC device campson a GERAN or a UTRAN, and the attach procedure and the TAU procedureare performed when the MTC device camps on an E-UTRAN.

The MTC device 100 transmits an attach request/RAU (Routing Area Update)request/TAU (Tracking Area Update) request message to an MME/SGSN 510via an (e)NodeB 200. Then, the MME/SGSN 510 transmits a location updaterequest to an HSS/HLR 540. The HSS/HLR transmits a location updateacknowledgement message to the MME/SGSN 510. Then, the MME/SGSN 510transmits an attach/RAU/TAU accept message to the MTC device 100.

In this case, the attach accept message may include information as shownin Table 3 or Table 4 below. Table 3 shows an attach accept message fora case where the MTC device camps on the E-UTRAN and performs an attachrequest to a core network, and Table 4 shows an attach accept messagefor a case where the MTC device camps on the GERAN/UTRAN and performsthe attach request to the core network.

TABLE 3 Information Description Attach accept Message identity messageidentity Attach result Indicate an attach result, for example, a successor a failure T3412 value Timer value for periodic TAU T3402 value Timerstarting at an attach failure T3412 extended Value extended from T3412value to be value longer than periodic TAU

TABLE 4 Information Description Attach accept message Message identityidentity Attach result Indicate an attach result, for example, a successor a failure Periodic RA update Timer value for periodic RAU timer value(T3312 value) T3302 value Timer starting at an attach failure T3312extended value Value extended from T3312 value to be longer thanperiodic RAU

Further, the TAU accept message may include information as shown inTable 5 below.

TABLE 5 Information Description TAU accept Message identity messageidentity TAU result Indicate an update result, for example, a success ora failure T3412 value Timer value for periodic TAU T3402 value Timerstarting at a TAU failure T3412 extended Value extended from T3412 valueto be value longer than periodic TAU

Further, the RAU accept message may include information as shown inTable 6 below.

TABLE 6 Information Description RAU accept Message identity messageidentity RAU result Indicate an update result, for example, a success ora failure Periodic RA update Timer value for periodic RAU timer value(T3312 value) T3302 value Timer starting at an RAU failure T3312extended Value extended from T3312 value to be value longer thanperiodic RAU

In Table 3 and Table 5 above, the T3412 value is a value for allowingthe MTC device 100 to perform periodic TAU. However, in order to reducea network load caused by the periodic TAU, the T3412 extended valueexists so that the TAU can be performed with a longer period. The T3412extended value may be configured in the MME 510, or may be stored in theHSS 540 as subscriber information. The MME 510 may select any one of theT3412 value and the T3412 extended value and may apply the selectedvalue to the MTC device 100.

In Table 4 and Table 6 above, the T3312 value is a value for allowingthe MTC device 100 to perform periodic RAU. However, in order to reducea network load caused by the periodic RAU, the T3312 extended valueexists so that the RAU can be performed with a longer period. The T3312extended value may be configured in the SGSN 510, or may be stored inthe HSS 540 as subscriber information. The SGSN 510 may select any oneof the T3312 value and the T3312 extended value and may apply theselected value to the MTC device 100.

Meanwhile, when the MTC device 100 receives the accept message, severalpieces of timer information included in the accept message areconfirmed. Further, the MTC device 100 starts a required timer amongseveral timers included in the accept message, for example, a periodicaccess (or location update) related timer. For example, the MTC device100 runs a timer according to a value of the T3312 timer for a periodicRAU procedure. Alternatively, the MTC device 100 runs the timeraccording to a value of the T3412 timer for a periodic TAU procedure.Alternatively, the MTC device 100 runs the timer according to a value ofthe T3412 extended timer for a TAU procedure with a longer period.Alternatively, the MTC device 100 runs the timer according to a value ofthe T3312 extended timer for an RAU procedure with a longer period. Thetimer managed by the MTC device 100 may be as shown in Table 7 or Table8 below.

Table 7 below shows a GPRS mobility management timer related to theattach procedure and the RAU procedure.

TABLE 7 TIMER TIMER NUM VALUE CAUSE OF START NORMAL STOP ON EXPIRY T3302Default When the attach fails and When the attach At expiry, the attach12 min the attempt count is procedure is procedure or the greater thanor equal to 5 initiated RAU procedure is When the RAU fails and When theRAU initiated the attempt counter is procedure is greater than or equalto 5 initiated T3312 Default In A/Gb mode, when the In A/Gb mode,Periodic RAU 54 min READY state is released, when entering the procedureis initiated In Iu mode, when the READY state if the attach is not forPMM-CONNECTED In Iu mode, when emergency bearer mode is released.entering the services. PMM-CONNECTED mode

Table 8 below shows an EPS mobility management timer related to anattach procedure and a TAU procedure.

TABLE 8 TIMER TIMER NUM VALUE CAUSE OF START NORMAL STOP ON EXPIRY T3402Default When the attach or When the attach The attach or TAU 12 min TAUfails and the or TAU request procedure is attempt count is greatermessage is initiated than or equal to 5 transmitted T3410 15 s Theattach request When the attach Start T3411 or T3402 message istransmitted accept or reject message is received T3411 10 s When theattach fails When the attach The attach request due to failure in lowerrequest message or TAU request layer or T3410 timeout, or TAU requestmessage is retransmitted or when the attach is message is rejectedtransmitted When the TAU fails due to failure in low layer or T3430timeout, or when the TAU is rejected T3412 Default In the EMM- Whenentering The periodic TAU 54 min. REGISTERED state, state the EMM-procedure is when the EMM- DEREGISTERED initiated if the CONNECTED modeis state or when attach is not for released entering the emergencybearer EMM-CONNECTED services mode It is implicitly detached from thenetwork if the attach is for emergency bearer services

The MTC device 100 monitors an expiry of a periodic access (or locationupdate) relater timer, for example, a T3312 timer or a T3312 extendedtimer or a T3412 timer or a T3412 extended timer.

At the expiry of the periodic access (or location update) related timer(e.g., the T3312 timer, the T3312 extended timer, the T3412 timer, orthe T3412 extended timer), the MTC device 100 may transmit a periodicRAU request message or a periodic TAU request message to the MME/SGSN510 via the (e)NodeB 200. The periodic access (or location update)related timer and an operation of a UE related to the timer may be foundin the standard document 3GPP TS 23.401, TS 23.060, TS 24.301, TS24.008.

Meanwhile, the MTC device 100 may perform the TAU/RAU procedure, so thatthe network node can perform MTC related monitoring as shown in FIG. 9in regards to a core network access (or a location update). However, oneproblem may occur in this case. For example, regarding that the MTCdevice 100 performs the TAU/RAU procedure to access a core network (orto update a location), as shown in FIG. 9, the network node may performMTC related monitoring by confirming whether an access to the corenetwork (or location update) is normally achieved by the MTC device 100with a specific period. By reference, an example of the monitoring mayinclude a location change of the MTC device or a loss of a connectivityto the network. However, the following problem may occur in the MTCrelated monitoring method. For example, a problem may occur when theperiodic access (or location update) related timer (e.g., a T3312 timer,a T3312 extended timer, a T3412 timer, or a T3412 extended timer) andthe MTC related monitoring do not have the same period. Morespecifically, if the network node performs monitoring when a period ofthe MTC related monitoring is arrived at a time at which the MTC device100 does not perform the TAU/RAU procedure since the periodic access (orlocation update) related timer has not been expired yet, the networknode may erroneously determine that the MTC device 100 does not have anormal access to the network.

Accordingly, a method of solving the aforementioned problem is describedhereinafter. The MTC monitoring method proposed in the present inventionmay be implemented by combining one or more methods described below.

In a first method, a network node may configure/adjust a value of aperiodic access (or location update) related timer (e.g., a timer forperiodic TAU/RAU) (e.g., a T3312 timer, a T3312 extended timer, a T3412timer, or a T3412 extended timer) (e.g., a subscribed periodic RAU/TAUtimer) by considering a time value (i.e., D_max) capable of determiningthat a monitoring event is detected (e.g., a time value for detecting anevent regarding a change of a network point to which the MTC device 100has an access, or a time value capable of determining that a networkaccess of the MTC device 100 is disconnected, etc.) and/or a period(i.e., D_period) for detecting whether a specific monitoring eventoccurs (e.g., a period for detecting whether there is a change in anetwork point to which the MTC device 100 has an access or a periodcapable of determining that a network access of the MTC device 100 isdisconnected). On the contrary, the network node may configure/adjust atime value (i.e., D_max) capable of determining that a monitoring eventis detected and/or a period (i.e., D_period) for detecting whether aspecific monitoring event occurs, by considering a periodic access (orlocation update) related timer (e.g., a timer for periodic TAU/RAU).

In a second method, if the network node performs monitoring regardingthat the MTC device 100 performs a network access (or location update)to a core network through a TAU/RAU procedure, the network node whichperforms the monitoring may configure/change/manage a value of aperiodic access (or location update) related timer (e.g., a timer forperiodic TAU/RAU).

Hereinafter, the first method is described with reference to FIG. 11 andFIG. 12, and the second method is described with reference to FIG. 13and FIG. 14.

FIG. 11 is a flowchart showing a procedure of performing MTC monitoringaccording to the first method proposed in the present specification.

As can be seen from FIG. 11, according to the first method proposed inthe present specification, an HSS/HLR 540 configures/adjusts any one ofan MTC monitoring related timer and the periodic access (or locationupdate) related timer (e.g., a T3312 timer, a T3312 extended timer, aT3412 timer, or a T3412 extended timer) (e.g., a subscribed periodicRAU/TAU timer value) on the basis of the other one. The MTC monitoringrelated timer is associated with a time value (i.e., D_max) capable ofdetermining that a monitoring event is detected and/or a period (i.e.,D_period) for detecting whether a specific monitoring event occurs.

Detailed descriptions are as followed. However, descriptions similar tothose of FIG. 9 will not be repeated, and the aforementioneddescriptions will be applied in this case.

1) To start monitoring, an SCS/AS 620 transmits a monitoring actionrequest message to an MTC-IWF 610. In this case, the MTC monitoringrelated timer (e.g., D_max, D_period) may be transmitted together. TheMTC monitoring related timer may be transmitted together with associatedother monitoring event related information (e.g., a type of a monitoringevent to be detected, an ID of SCS/AS for sending a report upondetection of the event, etc.). In addition, if there are a plurality ofmonitoring events to be detected, an MTC monitoring related timer mayexist for each type, and one MTC monitoring related timer may exist.This is applied throughout the present invention.

2˜3) Upon reception of the request, the MTC-IWF 610 authenticateswhether an SCS/AS 620 has a right for the request, and confirms whetherthe request of the SCS/AS 620 is beyond a predetermined allocationcriterion. If the confirmation result shows that the request of theSCS/AS 620 is acceptable, the MTC-IWF 610 transmits to the SCS/AS 620 amonitoring action response including a value indicating a success of therequest.

4˜6) Next, the MTC-IWF 610 transmits monitoring event data including theMTC monitoring related timer (e.g., D_max, D_period) to the HSS/HLR 540.The HSS/HLR 540 configures/adjusts any one of the MTC monitoring relatedtimer (e.g., D_max, D_period) and the periodic access (or locationupdate) related timer (e.g., a T3312 timer, a T3312 extended timer, aT3412 timer, or a T3412 extended timer) (e.g., a subscribed periodicRAU/TAU timer value) on the basis of the other one. The HSS/HLR 540transmits a response for a message received in the step 4. If the MTCmonitoring related timer (e.g., D_max, D_period) is configured/adjustedin the step 5, the HSS/HLR 540 may allow the response to include theconfigured/adjusted MTC monitoring related timer.

7˜8) Meanwhile, the MTC device 100 transmits an attach request to theMME/SGSN 510. Then, the MME/SGSN 510 transmits a location update requestmessage to the HS S/HLR 540.

9) The HSS/HLR 540 transmits to the MME/SGSN 510 the periodic access (orlocation update) related timer (e.g., a timer for periodic TAU/RAU)(e.g., one or more of a T3312 timer, a T3312 extended timer, a T3412timer, and a T3412 extended timer) (e.g., a subscribed periodic RAU/TAUtimer value) and monitoring event data by including them to a locationupdate acknowledgement. The monitoring event data includes theaforementioned MTC monitoring related timer (e.g., D_max, D_period).

10) Since the received location update response message includes themonitoring event data, the MME/SGSN 510 is configured to monitor anevent. Meanwhile, the configured event may be monitored by the MME/SGSN510, or according to a situation, may be monitored by the (e)NodeB 200and/or the P-GW 530.

11) The MME/SGSN 510 transmits an accept message for the attach requestto the MTC device 100 by including the periodic access (or locationupdate) related timer (e.g., one or more of the T3312 timer, the T3312extended timer, the T3412 timer, and the T3412 extended timer). As such,any one of the MTC monitoring related timer (e.g., D_max, D_period) andthe periodic access (or location update) related timer (e.g., a T3312timer, a T3312 extended timer, a T3412 timer, and a T3412 extendedtimer) is configured/adjusted on the basis of the other one, andthereafter each of them is delivered to the MME/SGSN 510. Therefore, theMME/SGSN 510 can correctly perform MTC monitoring. That is, a problemwhich occurs due to a difference between the aforementioned timers canbe solved. More specifically, for example, if the periodic access (orlocation update) related timer (e.g., a T3312 timer, a T3312 extendedtimer, a T3412 timer, and a T3412 extended timer) is adjusted byconsidering the MTC monitoring related timer (e.g., D_max, D_period), itis possible to avoid a situation in which the MME/SGSN 510 wronglydetermines that an event occurs when the event does not occur inpractice. For this, for example, a value of the periodic access (orlocation update) related timer (e.g., a T3312 timer, a T3312 extendedtimer, a T3412 timer, and a T3412 extended timer) may be configured to avalue equal to a smaller value between the MTC monitoring relatedtimers, e.g., D_max and D_period, or may be configured to a valuesmaller than a smaller value between D_max information and D_periodinformation. Meanwhile, when a value of the periodic access (or locationupdate) related timer is configured or adjusted/updated, not only theMTC monitoring relater timer (e.g., D_max, D_period) but also otherinformation (for example, information on a monitoring event, subscriberinformation, an operator policy, a network status, a feature of an MTCdevice, whether to perform roaming of the MTC device, etc.) may also beconsidered.

Meanwhile, although it is described that the periodic access (orlocation update) related timer, e.g., a periodic TAU/RAU related timer,can be configured/adjusted by the HSS/HLR 540 on the basis of the MTCmonitoring related timer (e.g., D_max, D_period), a new timer configuredon the basis of the MTC monitoring related timer (e.g., D_max, D_period)may be alternatively provided. When a value of the newly defined timeris delivered to a network node which is an entity for monitoring (e.g.,the MME/SGSN 510), the network node (e.g., the MME/SGSN 510) mayapply/adjust the periodic access (or location update) related timer onthe basis of the newly defined timer.

In addition, instead of always considering the MTC monitoring relatedtimers, e.g., D_max and D_period, as described above, the periodicaccess (or location update) related timer may be configured/updated byconsidering only D_max as a modified example or the periodic access (orlocation update) related timer may be configured/updated by consideringonly D_period.

In addition, whenever the periodic access (or location update) relatedtimer or information having an effect on the value is updated, theHSS/HLR 540 may provide the updated result to the MMS/SGSN 510 which isan entity for the monitoring. In addition, whenever the MTC monitoringrelated timer (e.g., D_max, D_period) is updated, the HSS/HLR 540 mayprovide the updated result to the MMS/SGSN 510 which is an entity forthe monitoring.

FIG. 12 is a flowchart showing another procedure of performing MTCmonitoring according to the first method proposed in the presentspecification.

As can be seen from FIG. 12, according to the first method proposed inthe present specification, an HSS/HLR 540 configures any one of an MTCmonitoring related timer and the periodic access (or location update)related timer (e.g., a T3312 timer, a T3312 extended timer, a T3412timer, or a T3412 extended timer) (e.g., a subscribed periodic RAU/TAUtimer value) on the basis of the other one. The MTC monitoring relatedtimer is associated with a time value (i.e., D_max) capable ofdetermining that a monitoring event is detected and/or a period (i.e.,D_period) for detecting whether a specific monitoring event occurs. Inthis case, several embodiments such as an option a and an option b mayexist according to where the MTC monitoring related timer is stored.According to the option a, the MTC monitoring related timer, e.g., atime value (i.e., D_max) capable of determining that a monitoring eventis detected, and a period (i.e., D_period) for detecting whether aspecific monitoring event occurs may be stored in the HSS/HLR 540.Alternatively, according to the option b, it may be provided by theSCS/AS 620.

Detailed descriptions are as followed. However, descriptions similar tothose of FIG. 9 will not be repeated, and the aforementioneddescriptions will be applied in this case.

0) The MTC device 100 performs an attach procedure to a network. Detailsof the attach procedure may be found in the standard documents 3GPP TS23.401 and TS 23.060.

1) To start monitoring, the SCS/AS 620 transmits a monitoring actionrequest to an MTC-IWF 610. In this case, according to the option b, anMTC monitoring related timer (e.g., D_max, D_period) may be transmittedtogether.

2˜3) Upon reception of the request, the MTC-IWF 610 authenticateswhether the SCS/AS 620 has a right for the request, and confirms whetherthe request of the SCS/AS 620 is beyond a predetermined allocationcriterion. If the confirmation result shows that the request of theSCS/AS 620 is acceptable, the MTC-IWF 610 transmits to the SCS/AS 620 amonitoring action response including a value indicating a success of therequest.

4˜6) Next, according to the option a, since the MTC monitoring relatedtimer (e.g., D_max, D_period) is stored in the HSS/HLR 540, the MTC-IWF610 transmits a subscriber information request message to the HSS/HLR540 to acquire it. The subscriber information request message istransmitted to acquire a variety of information for an MTC device, suchas routing information (i.e., serving node information) for the MTCdevice, or the like, in addition to the MTC monitoring related timerinformation. A procedure of requesting and acquiring the subscriberinformation may also be applied to the option b. In this case, theHSS/HLR 540 may configure/adjust any one of the MTC monitoring relatedtimer (e.g., D_max, D_period) and the periodic access (or locationupdate) related timer (e.g., the T3312 timer, the T3312 extended timer,the T3412 timer, or the T3412 extended timer) (e.g., a subscribedperiodic RAU/TAU timer value) in advance on the basis of the other one.Then, the HSS/HLR 540 transmits the MTC monitoring related timer (e.g.,D_max, D_period) among the configured/adjusted timers to the MTC-IWF610.

However, according to the option b, the monitoring event data includingthe MTC monitoring related timer (e.g., D_max, D_period) is delivered tothe HSS/HLR 540 via the MTC-IWF 610. After (or before) transmitting aresponse for the delivery, the HSS/HLR 540 configures a value of theperiodic access (or location update) related timer (e.g., the T3312timer, the T3312 extended timer, the T3412 timer, or the T3412 extendedtimer) (e.g., a subscribed periodic RAU/TAU timer) on the basis of thereceived MTC monitoring related timer (e.g., D_max, D_period).

7˜8) In the step 5a or 6b, if the HSS/HLR 540 adjusts/updates theperiodic access (or location update) related timer (e.g., a T3312 timer,a T3312 extended timer, a T3412 timer, or a T3412 extended timer) (i.e.,a subscribed periodic RAU/TAU timer value), the adjusted/updated timerinformation is transmitted to the MME/SGSN 510, i.e., the serving nodeof the MTC device 100. The MME/SGSN 510 transmits a response for areceived message to the HSS/HLR 540.

9˜10) Meanwhile, the MTC-IWF 610 determines the network node forperforming the monitoring, on the basis of information received from theSCS/AS 620 and the HSS/HLR 540. If the network node for performing themonitoring is determined as the MME/SGSN 510, the MTC-IWF 610 transmitsto the MME/SGSN 510 a request including monitoring event data. Themonitoring event data includes the aforementioned MTC monitoring relatedtimer (e.g., D_max, D_period). The MME/SGSN 510 transmits a response tothe MTC_IWF 610. The steps 9 and 10 may be performed simultaneously withthe steps 7 and 8.

11˜12) Meanwhile, the MTC device 100 transmits a TAU/RAU request to theMME/SGSN 510. Then, the MME/SGSN 510 transmits to the MTC device 100 anaccept message for the TAU/RAU request by including the periodic access(or location update) related timer (e.g., one or more of a T3312 timer,a T3312 extended timer, a T3412 timer, or a T3412 extended timer).

The MME/SGSN 510 is configured to monitor an MTC event after the step 9.The start of the monitoring event detection may be performed after thestep 11 or 12 in practice. In addition, instead of transmitting arequest including monitoring event data by the MTC-IWF 610 to theMME/SGSN 510 as shown in the step 9, the HSS/HLR 540 may transmit therequest including the monitoring event data to the MME/SGSN 510. Thismay be performed in combination with the step 7.

As shown in FIG. 12, any one of the MTC monitoring related timer (e.g.,D_max, D_period) and the periodic access (or location update) relatedtimer (e.g., a T3312 timer, a T3312 extended timer, a T3412 timer, and aT3412 extended timer) is configured/adjusted on the basis of the otherone, and thereafter each of them is delivered to the MME/SGSN 510.Therefore, the MME/SGSN 510 can correctly perform MTC monitoring. Thatis, a problem which occurs due to a difference between theaforementioned timers can be solved. More specifically, for example, ifthe periodic access (or location update) related timer (e.g., a T3312timer, a T3312 extended timer, a T3412 timer, and a T3412 extendedtimer) is adjusted by considering the MTC monitoring related timer(e.g., D_max, D_period), it is possible to avoid a situation in whichthe MME/SGSN 510 wrongly determines that an event occurs when the eventdoes not occur in practice. For this, for example, a value of theperiodic access (or location update) related timer (e.g., a T3312 timer,a T3312 extended timer, a T3412 timer, and a T3412 extended timer) maybe configured to a value equal to a smaller value between the MTCmonitoring related timers, e.g., D_max and D_period, or may beconfigured to a value smaller than a smaller value between D_maxinformation and D_period information. Meanwhile, when a value of theperiodic access (or location update) related timer is configured oradjusted/updated, not only the MTC monitoring relater timer (e.g.,D_max, D_period) but also other information (for example, information ona monitoring event, subscriber information, an operator policy, anetwork status, a feature of an MTC device, whether to perform roamingof the MTC device, etc.) may also be considered.

On the other hand, according to the option a, the MTC monitoring relatedtimer (e.g., D_max, D_period) is configured/stored in the HSS/HLR 540,and the timer may be dynamically configured/updated. The dynamicconfiguration/update may be performed when the HSS/HLR 540 providesinformation of monitoring event data including the MTC monitoringrelated timer (e.g., D_max, D_period). In this method, the SCS/AS 620may provide the information to the MTC-IWF 610 through the Tsp interfaceshown in FIG. 7, and the MTC-IWF 610 may provide the information to theHSS/HLR 540 through the S6m interface.

Meanwhile, although it is described that the periodic access (orlocation update) related timer, e.g., a periodic TAU/RAU related timer,can be configured/adjusted by the HSS/HLR 540 on the basis of the MTCmonitoring related timer (e.g., D_max, D_period), a new timer configuredon the basis of the MTC monitoring related timer (e.g., D_max, D_period)may be alternatively provided. When a value of the newly defined timeris delivered to a network node which is an entity for monitoring (e.g.,the MME/SGSN 510), the network node (e.g., the MME/SGSN 510) mayapply/adjust the periodic access (or location update) related timer onthe basis of the newly defined timer.

In addition, instead of always considering the MTC monitoring relatedtimers, e.g., D_max and D_period, as described above, the periodicaccess (or location update) related timer may be configured/updated byconsidering only D_max as a modified example or the periodic access (orlocation update) related timer may be configured/updated by consideringonly D_period.

In addition, whenever the periodic access (or location update) relatedtimer or information having an effect on the value is updated, theHSS/HLR 540 may provide the updated result to the MMS/SGSN 510 which isan entity for the monitoring.

In addition, in FIG. 11 and FIG. 12, if the HSS/HLR 540 is not availableto configure/update the periodic access (or location update) relatedtimer by considering the MTC monitoring related timer (e.g., D_max,D_period) (e.g., when D_max information and D_period information arerelatively small values and thus it is impossible to configure/updateinformation having an effect to a value of the periodic access (orlocation update) related timer by using the same or smaller value), thismay be reported to one or more nodes (e.g., the MTC_IWF 610 and theSCS/AS 620) related to the monitoring.

FIG. 13 is a flowchart showing a procedure of performing MTC monitoringaccording to the second method proposed in the present specification.

As can be seen from FIG. 13, according to the second method proposed inthe present specification, a network node for performing MTC monitoring,e.g., the MME/SGSN 510, may configure the periodic access (locationupdate) related timer (e.g., the T3312 timer, the T3312 extended timer,the T3412 timer, or the T3412 extended timer) on the basis of the MTCmonitoring related timer. In this case, in addition to the MTCmonitoring related timer, the MME/SGSN 510 may consider one or morepieces of additional information as shown in Table 9 above. However, thepresent invention is not limited thereto, and thus a variety ofinformation related to a monitoring operation in terms of an MTC servicemay be considered, and also a variety of information stored in orprovided by the existing network or the MTC device may be considered.

TABLE 9 Subscriber information (e.g., timer related information inassociation with mobility management acquired from HSS/HLR (e.g.,subscribed periodic RAU/TAU timer information, etc.)) MTC devicecapability information and/or priority information (e.g., whether it isan MTC device configured with a low priority, an MTC device configuredwith a dual priority, or an MTC device applied with a timer forperforming RAU/TAU with a longer period, etc.) HPLMN and/or VPLMNoperator policy MTC monitoring related information Information acquiredfrom another node (e.g., SCS/AS, MTC-IWF, S-GW, P-GW, GGSN, etc.)Information acquired from another serving node (e.g., in case of MME,information acquired from SGSN, and in case of SGSN, informationacquired from MME) Network status information (e.g., RAN congestionstatus, core network congestion status, etc.) Values of timersassociated with mobility management related operation Values of timersassociated with session management related operation

This will be described below in detail by referring to FIG. 13.

1˜3) These steps are the same as those described in FIG. 11 and FIG. 12,and thus redundant descriptions will be omitted.

4˜5) Monitoring event data including the MTC monitoring related timer(e.g., D_max, D_period) is delivered from the SCS/AS 620 to the HSS/HLR540 via the MTC-IWF 610. The HSS/HLR 540 transmits a response for thedelivery.

6˜7) Meanwhile, the MTC device 100 transmits an attach request to theMME/SGSN 510. Then, the MME/SGSN 510 transmits a location update requestmessage to the HS S/HLR 540.

8) The HSS/HLR 540 transmits the monitoring event data to the MME/SGSN510 by including the data to a location update acknowledgement. Themonitoring event data includes the MTC monitoring related timer (e.g.,D_max, D_period).

9) Then, the MME/SGSN 510 adjusts/configures the received periodicaccess (location update) related timer (e.g., a timer for periodicTAU/RAU) (e.g., the T3312 timer, the T3312 extended timer, the T3412timer, or the T3412 extended timer)(e.g., a subscribed periodic RAU/TAUtimer value) by considering the MTC monitoring related timer (e.g.,D_max, D_period). In this case, as described above, in addition to theMTC monitoring related timer, one or more pieces of additionalinformation may be considered as shown in Table 9 above.

10) Since the received location update response message includes themonitoring event data, the MME/SGSN 510 is configured to monitor anevent. Meanwhile, the configured event may be monitored by the MME/SGSN510, or according to a situation, may be monitored by the (e)NodeB 200and/or the P-GW 530.

11) The MME/SGSN 510 transmits an accept message for the attach requestto the MTC device 100 by including the adjusted/configured periodicaccess (or location update) related timer (e.g., one or more of theT3312 timer, the T3312 extended timer, the T3412 timer, and the T3412extended timer).

In addition, the MME/SGSN 510 may provide the HSS/HLR 540 with theconfigured/adjusted periodic access (or location update) related timer(e.g., a T3312 timer, a T3312 extended timer, a T3412 timer, or a T3412extended timer) (e.g., a subscribed periodic RAU/TAU timer value). Uponreceiving this, the HSS/HLR 540 may update/store a periodic access (orlocation update) related timer stored therein (e.g., the T3312 timer,the T3312 extended timer, the T3412 timer, or the T3412 extended timer)(e.g., the subscribed periodic RAU/TAU timer value). In doing so, theHSS/HLR 540 may provide the updated periodic access (or location update)related timer to another serving node (e.g., MME or SGSN) whentransmitting subscriber information.

Meanwhile, after the MME/SGSN 510 configures/adjusts the periodic access(or location update) related timer (e.g., the T3312 timer, the T3312extended timer, the T3412 timer, or the T3412 extended timer) (e.g., thesubscribed periodic RAU/TAU timer value), there may be a change in theaforementioned one or more pieces of additional information. In thiscase, if the one or more pieces of additional information are acquiredby using the HSS/HLR 540, the HSS/HLR may report the changed additionalinformation to the MME/SGSN 510. Then, the MME/SGSN 510 may update theadjusted periodic access (or location update) related timer. As such,when the MME/SGSN 510 performs the update, this may also be reported tothe HSS/HLR 540.

In addition, the MME/SGSN 510 may store in a UE context theconfigured/adjusted periodic access (or location update) related timerinformation, in particular, periodic access (or location update) relatedtimer information which is included when transmitting an attach accessmessage to the MTC device 100. Therefore, when the MTC device 100changes a serving node (i.e., MME/SGSN), the existing serving node isallowed to provide and utilize the periodic access (or location update)related timer to a new serving node. This may be applied throughout thepresent invention.

Meanwhile, although the HSS/HLR 540 transmits monitoring event data tothe MME/SGSN 510 which is a network node for performing monitoring as inthe steps 9 and 8 in FIG. 11 and FIG. 13, unlike this, the MTC-IWF 610may transmit the monitoring event data to the MME/SGSN 510. In thiscase, the MTC-IWF 610 which receives a monitoring action request fromthe SCS/AS 620 performs an interaction with the HSS/HLR 540 to acquirerouting information (i.e., serving node information) for the MTC device100, but the MTC device 100 has not performed an attach to a networkyet. For this reason, serving node information does not exist.Therefore, when the MTC device 100 is reachable, the MTC-IWF 610 mayrequest the HSS/HLR 540 to notify this. Accordingly, when the MTC device100 performs an attach to the network, the MTC-IWF 610 may acquireserving node information of the MTC device 100 from the HSS/HLR 540, andmay request the serving node to perform monitoring by transmittingmonitoring event data. This may be applied throughout the presentinvention.

FIG. 14 is a flowchart showing another procedure of performing MTCmonitoring according to the second method proposed in the presentspecification.

0) The MTC device 100 performs an attach procedure to a network. Detailsof the attach procedure may be found in the standard documents 3GPP TS23.401 and TS 23.060.

1˜3) These steps are the same as those described in FIG. 11 to FIG. 13,and thus redundant descriptions will be omitted.

4˜5) As described above, several embodiments such as an option a and anoption b may exist according to where the MTC monitoring related timeris stored.

According to the option a, since the MTC monitoring related timer (e.g.,D_max, D_period) is stored in the HSS/HLR 540, the MTC-IWF 610 transmitsa subscriber information request message to the HSS/HLR 540 to acquireit. Then, the HSS/HLR 540 transmits the MTC monitoring related timer(e.g., D_max, D_period) to the MTC-IWF 610. The subscriber informationrequest message is transmitted to acquire a variety of information foran MTC device, such as routing information (i.e., serving nodeinformation) for the MTC device, or the like, in addition to the MTCmonitoring related timer information. A procedure of requesting andacquiring the subscriber information may also be applied to the optionb.

According to the option b, monitoring event data including the MTCmonitoring related timer (e.g., D_max, D_period) is delivered from theSCS/AS 620 to the HSS/HLR 540 via the MTC-IWF 610. The HSS/HLR 540transmits a response for the delivery.

6˜7) Meanwhile, the MTC-IWF 610 determines the network node forperforming the monitoring, on the basis of information received from theSCS/AS 620 and the HSS/HLR 540. If the network node for performing themonitoring is determined as the MME/SGSN 510, the MTC-IWF 610 transmitsto the MME/SGSN 510 a request including monitoring event data. Themonitoring event data includes the aforementioned MTC monitoring relatedtimer (e.g., D_max, D_period). The MME/SGSN 510 transmits a response tothe MTC-IWF 610.

8) Meanwhile, the MTC device 100 transmits a TAU/RAU request to theMME/SGSN 510.

9) Then, the MME/SGSN 510 adjusts/configures the received periodicaccess (location update) related timer (e.g., a timer for periodicTAU/RAU) (e.g., the T3312 timer, the T3312 extended timer, the T3412timer, or the T3412 extended timer)(e.g., a subscribed periodic RAU/TAUtimer value) by considering the MTC monitoring related timer (e.g.,D_max, D_period). In this case, as described above, in addition to theMTC monitoring related timer, one or more pieces of additionalinformation may be considered as shown in Table 9 above.

10) Subsequently, the MME/SGSN 510 transmits to the MTC device 100 anaccept message for the TAU/RAU request by including theconfigured/adjusted periodic access (or location update) related timer(e.g., one or more of a T3312 timer, a T3312 extended timer, a T3412timer, or a T3412 extended timer).

The MME/SGSN 510 is configured to monitor an MTC event after the step 6.The start of the monitoring event detection may be performed after thestep 8, 9, or 10 in practice. In addition, instead of transmitting arequest including monitoring event data by the MTC-IWF 610 to theMME/SGSN 510 as shown in the step 6, the HSS/HLR 540 may transmit therequest including the monitoring event data to the MME/SGSN 510.

In addition, the MME/SGSN 510 may provide the HSS/HLR 540 with theconfigured/adjusted periodic access (or location update) related timer(e.g., a T3312 timer, a T3312 extended timer, a T3412 timer, or a T3412extended timer) (e.g., a subscribed periodic RAU/TAU timer value). Uponreceiving this, the HSS/HLR 540 may update/store a periodic access (orlocation update) related timer stored therein (e.g., the T3312 timer,the T3312 extended timer, the T3412 timer, or the T3412 extended timer)(e.g., the subscribed periodic RAU/TAU timer value). In doing so, theHSS/HLR 540 may provide the updated periodic access (or location update)related timer to another serving node (e.g., MME or SGSN) whentransmitting subscriber information.

Meanwhile, after the MME/SGSN 510 configures/adjusts the periodic access(or location update) related timer (e.g., the T3312 timer, the T3312extended timer, the T3412 timer, or the T3412 extended timer) (e.g., thesubscribed periodic RAU/TAU timer value), there may be a change in theaforementioned one or more pieces of additional information. In thiscase, if the one or more pieces of additional information are acquiredby using the HSS/HLR 540, the HSS/HLR may report the changed additionalinformation to the MME/SGSN 510. Then, the MME/SGSN 510 may update theadjusted periodic access (or location update) related timer. As such,when the MME/SGSN 510 performs the update, this may also be reported tothe HSS/HLR 540.

In addition, the MME/SGSN 510 may store in a UE context theconfigured/adjusted periodic access (or location update) related timerinformation, in particular, periodic access (or location update) relatedtimer information which is included when transmitting a TAU accept orRAU accept message to the MTC device 100. Therefore, when the MTC device100 changes a serving node (i.e., MME/SGSN), the existing serving nodeis allowed to provide and utilize the periodic access (or locationupdate) related timer to a new serving node. This may be appliedthroughout the present invention.

Meanwhile, in FIG. 13 and FIG. 14, if the HSS/HLR 540 is not availableto configure/update the periodic access (or location update) relatedtimer by considering the MTC monitoring related timer (e.g., D_max,D_period) (e.g., when D_max information and D_period information arerelatively small values and thus it is impossible to configure/updateinformation having an effect to a value of the periodic access (orlocation update) related timer (e.g., a T3312 timer, a T3312 extendedtimer, a T3412 timer, or a T3412 extended timer) by using the same orsmaller value), this may be reported to one or more nodes (e.g.,HSS/HLR, MTC-IWF, SCS/AS) related to the monitoring.

FIG. 15 shows a modified example for the methods shown in FIG. 13 andFIG. 14.

Referring to FIG. 15, a network node for performing MTC monitoring,e.g., the MME/SGSN 510, may configure/adjust an MTC monitoring relatedtimer (e.g., D_max, D_period) on the basis of a periodic access (orlocation update) related timer. Since a signal flow shown in FIG. 15 canbe easily known from FIG. 13 and FIG. 14, detailed descriptions thereofwill be omitted. As described above, since the MMS/SGSN 510 can adjustthe MTC monitoring related timer provided by the MTC-IWF 610, if the MTCmonitoring related timer value is changed, the MME/SGSN 510 may reportthe changed MTC monitoring related timer value to the MTC-IWF 610.

FIG. 16 shows a modified example for the methods shown in FIG. 11 toFIG. 15.

As can be seen from FIG. 16, a network node related to MTC monitoring,e.g., the MTC-IWF 610, may configure any one of an MTC monitoringrelated timer and the periodic access (or location update) related timer(e.g., the T3312 timer, the T3312 extended timer, the T3412 timer, orthe T3412 extended timer) (e.g., a subscribed periodic RAU/TAU timervalue) on the basis of the other one. In this case, although it is shownin FIG. 16 that the MTC-IWF 610 adjusts timers, the timers may beconfigured/adjusted by the network node related to the MTC monitoring,e.g., a node such as an MTC monitoring server, a PCRF, an S-GW, the P-GW530, a GGSN, the SCS/AS 620, or an application server (AS).

More specifically, this is described as follows.

1˜3) These steps are the same as those described in FIG. 11, and thusredundant descriptions will be omitted.

4˜5) The MTC-IWF 610 requests the HSS/HLR 540 to transmit subscriberinformation, and receives the subscriber information. Information on theperiodic access (or location update) related timer may be included inthe received subscriber information. In addition, information on themonitoring related timer may be included in the received subscriberinformation.

6) On the basis of any one of the periodic access (or location update)related timer acquired from the HSS/HLR 540 or the MTC monitoringrelated timer (D_max, D_period) acquired from the HSS/HLR 540, theMTC-IWF 610 may configure/adjust the other one. In this case, one ormore pieces of additional information as shown in Table 9 above may beconsidered.

Although it is described up to now that the MTC-IWF 610 adjusts timersby referring to FIG. 16 for example, the timers may beconfigured/adjusted by the network node related to the MTC monitoring,e.g., a node such as an MTC monitoring server, a PCRF, an S-GW, the P-GW530, a GGSN, the SCS/AS 620, or an application server (AS).

Embodiments described in FIG. 11 to FIG. 16 above may be used by beingconfigured in a mutually combined manner.

Although the description of FIG. 9 to FIG. 16 focuses on a PacketSwitched (PS) network, the present invention is also applicable byextension to a Circuit Switched (CS) network. In addition, although theabove description focuses on time value information (D_max) capable ofdetermining that a specific monitoring event is detected and periodinformation (D_period) for detecting whether the specific monitoringevent occurs, the present invention is also applicable by extension toall time/period information which may have an effect on a periodiclocation registration operation of a UE. In addition, the presentinvention is also applicable not only to a periodic locationregistration related timer value of the UE but also other existinglocation registration related timer values and a timer value related toan MTC service.

In addition, the present invention is also applicable by extension notonly to a Mobility Management (MM) but also to a Session Management(SM). That is, although the aforementioned description focuses on an MMrelated timer in association with an MTC monitoring event detectable byan MM operation, the present invention is also applicable to an SMrelated timer in association with an MTC monitoring event detectable byan SM operation.

The content described up to now can be implemented in hardware. Thiswill be described with reference to FIG. 17.

FIG. 17 is a block diagram showing a structure of a network nodeaccording to an embodiment of the present invention.

As shown in FIG. 17, the network node, for example, the MME/SGSN 510,the HSS/HLR 540, or the MTC-IWF 610, respectively includes storageelements 511, 541, and 611, controllers 512, 542, and 612, andtransceivers 513, 543, and 613.

The storage elements 511, 541, and 611 store the method of FIG. 9 toFIG. 16.

The controllers 512, 542, and 612 control the storage elements 511, 541,and 611 and the transceivers 513, 543, and 613. More specifically, thecontrollers 512, 542, and 612 respectively execute the aforementionedmethods stored in the storage elements 511, 541, and 611. Further, thecontrollers 512, 542, and 612 transmit the aforementioned signals viathe transceivers 513, 543, and 613.

Although exemplary embodiments of the present invention have beendescribed above, the scope of the present invention is not limited tothe specific embodiments and the present invention may be modified,changed, or improved in various ways within the scope of the presentinvention and the category of the claims.

What is claimed is:
 1. A method for adjusting a timer value for a userequipment (UE), the method comprising: determining, by a homesubscribing server (HSS), a timer value for a routing area update (RAU)or a tracking area update (TAU) based on a maximum detection time periodof loss of connectivity, wherein the timer value for the RAU or the TAUis determined to be a smaller value than the maximum detection timeperiod of the loss of connectivity, wherein the loss of connectivity isrelated to signaling between the UE and a network, and wherein themaximum detection time period of the loss of connectivity is used fordetecting that the UE is no longer reachable for signaling to thenetwork; and transmitting, by the HSS, information including thedetermined timer value for the RAU or the TAU to a Mobility ManagementEntity (MME)/Serving General Packet Radio Service (GPRS) Supporting Node(SGSN).
 2. The method of claim 1, wherein the timer value for the RAU orthe TAU includes one or more of: a T3312 value for the RAU; a T3312extended value for the RAU; a T3412 value for the TAU; and a T3412extended value for the TAU.
 3. The method of claim 1, wherein themaximum detection time period of the loss of connectivity is fortransmitting an event to an application server (AS).
 4. The method ofclaim 1, wherein the timer value for the RAU or the TAU is set based onone or more of: subscriber information; capability information orpriority information of a Machine Type Communication (MTC) device;operator policy information; MTC monitoring related information;information acquired from another node; network status information;information associated with a mobility management related operation; andinformation association with a session management related operation. 5.The method of claim 1, wherein the maximum detection time period of theloss of connectivity is received from an application server (AS), andwherein the AS is a Machine Type Communication-InterWorking Function(MTC-IWF) or a service capability server.
 6. The method of claim 1,wherein the HSS stores an identifier (ID) of a Machine TypeCommunication (MTC) server.
 7. The method of claim 1, wherein the UE isa Machine Type Communication (MTC) device.
 8. The method of claim 1,wherein after the maximum detection time period of the loss ofconnectivity lapses, the loss of the connectivity is identified.
 9. Ahome subscription server (HSS) for adjusting a timer value for a userequipment (UE), the HSS comprising: a processor configured to determinea timer value for a routing area update (RAU) or a tracking area update(TAU) based on a maximum detection time period of the loss ofconnectivity, wherein the timer value for the RAU or the TAU isdetermined to be a smaller value than the maximum detection time periodof the loss of connectivity, wherein the loss of connectivity is relatedto signaling between the UE and a network, and wherein the maximumdetection time period of the loss of connectivity is used for detectingthat the UE is no longer reachable for signaling to the network; and atransceiver configured to transmit information including the determinedtimer value for the RAU or the TAU to a Mobility Management Entity(MME)/Serving General Packet Radio Service (GPRS) Supporting Node(SGSN).
 10. The HSS of claim 9, wherein the timer value for the RAU orthe TAU includes one or more of: a T3312 value for the RAU; a T3312extended value for the RAU; a T3412 value for the TAU; and a T3412extended value for the TAU.
 11. The HSS of claim 9, wherein the maximumdetection time period of the loss of connectivity is for transmitting anevent to an application server (AS).
 12. The HSS of claim 9, wherein thetimer value for the RAU or the TAU is set based on one or more of:subscriber information; capability information or priority informationof a Machine Type Communication (MTC) device; operator policyinformation; MTC monitoring related information; information acquiredfrom another node; network status information; information associatedwith a mobility management related operation; and informationassociation with a session management related operation.
 13. The HSS ofclaim 9, wherein the maximum detection time period of the loss ofconnectivity is received from an application server (AS), and whereinthe AS is a Machine Type Communication-InterWorking Function (MTC-IWF)or a service capability server.
 14. The HSS of claim 9, wherein the HSSstores an identifier (ID) of a Machine Type Communication (MTC) server.15. The HSS of claim 9, wherein the UE is a Machine Type Communication(MTC) device.
 16. The HSS of claim 9, wherein after the maximumdetection time period of the loss of connectivity lapses, the loss ofthe connectivity is identified.